Many college students in the US consider hookah smoking safer than smoking cigarettes, despite emerging evidence otherwise, a new study has found.

Researchers at the University of South Florida (USF) College of Public Health examined the prevalence of hookah use and described social and behavioural factors associated with hookah smoking among students at USF.

"The biggest surprise was the misperception about the dangers of hookah smoking," said Jaime Corvin, USF assistant professor of global health and principal investigator for the study.

"In general, the students we surveyed thought it was safer than cigarette smoking. They did not know the risks," Corvin said.

In recent years, while the prevalence of cigarette smoking has declined, the popularity of hookah and other alternative forms of tobacco use, including e-cigarettes, has increased among young adults.

Charcoal used to heat the tobacco in the hookah, which cools and filters the smoke through water, can raise health risks by producing high levels of carbon monoxide, metals, and cancer-causing chemicals, according to the Centers for Disease Control and Prevention (CDC).

While the science is still emerging, data accumulated so far indicates that using a water pipe to smoke tobacco poses serious health risks to smokers and others exposed to its secondhand smoke, researchers said.

"The World Health Organisation estimates that one 45-minute session of smoking hookah is equivalent to smoking 100 cigarettes," Corvin said.

In the 2012 cross-sectional USF study, researchers interviewed 478 undergraduate and graduate students at USF to evaluate their lifetime and current hookah use.

More than half of the students surveyed (54.4 per cent) reported using hookah at some point in their lives. The current prevalence of hookah use among the USF students (within the last 30 days) was 16.3 per cent - a finding consistent with other studies surveying college-aged students.

Hookah smoking was significantly associated with cigarette smoking but not with alcohol use.

While most respondents acknowledged that hookah smoking has harmful effects, more than half of the sample perceived hookah to be a safer alternative than cigarette smoking, and 13 per cent thought hookah wasn't harmful at all.

Regardless of their perception of harmfulness, 30 per cent of those who never smoked hookah reported they would consider smoking it in the future.

The reasons why students significantly underestimate the potential hazards smoking hookah were unclear.

Corvin suggests the lighter, softer smoke emitted from the water pipe and its fruity, pleasant smell may contribute to the perception that hookah is less risky than smoking cigarettes.